Clinician Brief: Hemorrhagic Fever with Renal Syndrome

Overview

Hemorrhagic fever with renal syndrome (HFRS) is a group of clinically similar illnesses caused by hantaviruses. The severity of the disease varies depending on the virus causing the infection. Hantaan and Dobrava virus infections usually cause severe symptoms, while Seoul, Saaremaa, and Puumala virus infections are usually more moderate.

Seoul virus occurs around the globe, including in the United States. Other hantaviruses cause HFRS in western Europe, Russia, Asia, and Scandinavia.

How it spreads

Hantaviruses are carried and spread by rodents. People can develop HFRS after becoming infected with these viruses when they:

• Breathe in aerosolized virus that gets stirred up during cleaning.
• Touch rodent urine, feces, or saliva, then touch their eyes, nose, or mouth.
• Expose broken skin to rodent body fluids or droppings.
• Touch objects contaminated with rodent body fluids and droppings.
• Eat food contaminated with rodent body fluids.

People who handle rodents as pets or for veterinary care can also be infected by a rodent bite. Transmission between people may occur but is extremely rare.

Signs and symptoms

HFRS is a severe and sometimes deadly disease that affects the kidneys. Symptoms of HFRS usually develop within 1 to 2 weeks after someone is exposed to hantavirus through a rodent. In rare cases, symptoms may take up to 8 weeks to develop.

Initial symptoms begin suddenly and include intense headaches, back and abdominal pain, fever, chills, nausea, and blurred vision. People may have a flushed face, eye inflammation or redness, or a rash.

Later symptoms can include:

• Low blood pressure
• Acute shock
• Vascular leakage
• Acute kidney failure, potentially causing severe fluid overload

The severity of the disease varies depending on the specific hantavirus causing the infection.

Reducing risk

People should avoid contact with rodent urine, droppings, saliva, and nesting materials. If mice or rats are in or around your home, it's important to clean up after them safely . Pet rodents, including pet rats, are not recommended for families with children 5-years old or younger, pregnant women, or people with weakened immune systems as they are at a greater risk of serious illness.

Safely caring for pet rats can help prevent diseases caused by hantaviruses. Pet owners can consult their veterinarians about testing new rats for hantaviruses before they are introduced into new homes, especially if they will be living with other rats in a home or breeding facility.

Keep wild rats (which naturally carry hantavirus) away from pet rats by taking steps to prevent rodent infestations.

If you have questions about your specific situation, contact your local health department.

Testing and diagnosis

CDC uses an enzyme-linked immunosorbent assay (ELISA) to detect IgM antibodies and diagnose acute infections with hantaviruses. This diagnostic method is used to diagnose both HPS and HFRS.

Diagnostic testing can be performed at:

• CDC
• State labs running the CDC-developed assay
• State public health labs using other diagnostic assays
• Commercial labs

The criteria to report Hantavirus-positive cases are based on the national case definition, which includes clinical symptoms (HPS or non-HPS) and acute laboratory diagnostic results, such as:

• IgM positive
• IgG positive with rising titers
• Immunohistochemistry (IHC) positive, or
• PCR positive

Treatment and recovery

Care for hantavirus infection typically includes supportive therapy:

• Carefully managing patient's hydration and electrolyte levels
• Maintaining correct oxygen and blood pressure levels
• Appropriately treating secondary infections.

Dialysis may be required to correct severe fluid overload.

If used early in the course of the disease, the antiviral ribavirin can be given intravenously to decrease illness and death from HFRS.

Complete recovery can take weeks to months.

Death rates for patients vary greatly depending on the specific virus causing HFRS, from less than 1 percent (Puumala virus) to up to 15 percent (Hantaan virus).

Related diseases

Another disease caused by hantaviruses is Hantavirus Pulmonary Syndrome. While HFRS causes mostly kidney system issues, HPS mostly involves lung damage and is found in the western hemisphere, including in the U.S.